That’s what jurors must decide in the first-degree murder trial of Brampton trucker Sukhchain Singh Brar, who killed his wife and set her on fire on Highway 402 near Sarnia early last year.

Brar was “cruelly unaware” of his wife’s infidelity until she told him on that trip, prompting his crime, stated the defence submission to jurors Wednesday.

“Hold him accountable for killing his wife. Manslaughter, that’s the verdict on the evidence,” defence lawyer Brennan Smart said during the fourth week of the Superior Court trial.

Smart said the provocation was Brar’s wife telling him he was not the father of their youngest child.

“The pillars of his existence were swept out from underneath him. . . . What could be more provocation than to have your existence in shambles?” said Smart.

The Crown must prove the murder charge, Smart said.

Brar, 52, is charged with the first-degree murder of Gurpreet Brar, 37, who was killed Jan. 31, 2016, as the couple travelled by transport truck on Highway 402.

Brar earlier testified through a Punjabi interpreter he lied to police officers at the early morning scene of the intense fire that destroyed the truck but not the trailer.

“He continues to lie to you about what happened in the truck,” assistant Crown attorney Melanie Nancekievill said in her closing submission to the jury.

Brar testified he put paper towels on top of his wife’s body in the truck before setting the fire but the paper was founded tucked under her torso, Nancekievill said.

Brar said debris fell during the fire, but debris doesn’t get tucked under when it falls, Nancekievill continued.

Brar struck his wife in the head four times with a large hammer and never missed, as there were no injuries to any other part of her body, said Nancekievill, urging jurors to reject Brar’s testimony he had lost control.

Brar’s one purpose in the repeated strikes was to kill his wife, Nancekievill said.

In his earlier testimony, Brar said he did not know how many times he had struck his wife.

In the fight that started as she was in the truck’s passenger seat and he was in driver’s seat, Brar said his head turned to stone.

Both Smart and Nancekievill referred to a photograph of the couple taken in India a few weeks before her death.

Smart directed the jury to a TV screen showing the image of the smiling couple.

“Is that somebody who is enraged with his wife?” Smart asked.

People smile when they are photographed and put on a happy face even when stressed, said Nancekievill, referring to that photo.

Jury deliberations on whether Brar planned to kill his wife or was suddenly provoked by her alleged admission of an affair are set to begin Thursday. Submissions by Crown and defence lawyers finished Wednesday, and the judge’s instructions to jurors started.

Brar testified earlier that he hit his wife with a hammer kept by the driver’s seat of the truck after she grabbed him by the neck. He then pushed her and she fell onto the sleeper bunk, where he hit her repeatedly, Brar had testified.

The attack occurred at a truck stop along Highway 402. He drove away with her bloodied body behind him in the sleeper before stopping to set the truck on fire about 3 a.m.

Medical evidence showed his wife was alive when Brar set the fire using fuel from containers he had in the truck.

He admitted lying to police to save himself so he could care for their children.

At the trial’s outset last month, Brar tried to plead guilty to manslaughter, but the Crown rejected his plea to the lesser offence.